The ACPI wakeup tool is a small command line
application that allows your Linux computer to
wake up from soft-off (S5) at a predetermined
time. It is ideal for situations where you want to
have a server turn off at night but power itself
on in the morning automatically.

Cpuspeedy allows you to change the clock speed and voltage of CPUs using
Linux's CPUFreq driver. It is a user space program, so it will work on
every processor supported by the kernel's CPUFreq driver.

FluxBat is an ACPI based battery monitor for the
fluxbox window manager. It includes two parts: a
daemon process that runs the update script and the
update script itself. The whole software contains
only about 100 lines of code and is easy to use by
including only one line in the menu configuration
file of fluxbox.

Genpower is a UPS monitoring program for Linux. It supports common UPSs like
APC, BackUPS, and Tripplite models. This is a updated version of an old
genpower utility found on Metalab, with added support for new UPSs.

MonAMI aims to be a standard place for monitoring
the availability and performance of services. It
can talk to many different monitoring systems
while remaining easy to configure. It has a plugin
structure, making it easy to add new things to
monitor or to integrate with new monitoring
systems.

Network UPS Tools (also known as NUT) is an extremely powerful and versatile client/server based approach to UPS monitoring. Products from a wide range of vendors (APC, Belkin, Best Power, MGE, Tripp-Lite, etc.) are supported. A shared UPS can be monitored by one host, notifcations being sent to the other hosts via authenticated TCP connections. A Web interface is available, as is a Windows client.

OSXControl allows you to shut down, reset or put
to sleep an Apple computer running OS X after a
set time lapse. A plugin architecture is supported
for user extensions. It also has automation
features and G4 optimization.